title: Changes in the amplitude of electrocardiogram QRS complexes during follow-up of heart failure patients.
abstract: BACKGROUND
  Changes in the electrocardiogram QRS amplitudes (ECGΔ) during follow-up of heart failure (HF) patients have not been clinically exploited heretofore.
  
  
  METHODS
  We examined ECGΔ during follow-up of HF patients by employing 42 triplets of ECGs, other laboratory and HF-related clinical data corresponding to clinical stability, worsening, and recovery from 37 HF patients.
  
  
  RESULTS
  The % changes (Δ%) in the summed QRS amplitude of all 12 leads (ΣQRS(12L)), 6 precordial leads (ΣQRS(V1-V6)), 6 limb leads (ΣQRS(6L)), leads I+II (ΣQRS(I + II)), and lead aVR were evaluated. Also relationships between the ECG variables and body weight (BW), percent body-fat, and B-type natriuretic peptide (BNP) were examined. The QRS amplitude(s) in all ECG variables decreased from clinical stability to worsening HF, and returned to baseline at recovery. During HF worsening, Δ% was highest in lead aVR (-15.3 ± 12.3%), followed by Δ% in ΣQRS(6L) (-12.9 ± 10.1%) and ΣQRS(I + II) (-12.1 ± 10.8%). At worsening HF and its recovery, Δ% in ΣQRS(6L) correlated with Δ% in percent body-fat (r = 0.333, P = .031; r = 0.308, P = .047). At recovery, Δ% in each ECG variable correlated with Δ% in BW. Receiver operating characteristic (ROC) analysis showed that ≥16% reduction of ΣQRS(6L) and ΣQRS(I + II) discriminated between stable and worsening HF, with a sensitivity of 43% and 40%, and specificity of 98% for both. ECG variables from limb lead(s) had as good area under the curve (AUC) (0.78-0.84) as BNP (AUC: 0.88) for identifying worsening HF.
  
  
  CONCLUSIONS
  Changes of the QRS amplitudes in ECGs are as useful for monitoring HF patients as BNP.
authors.affiliation: Division of Internal Medicine, Nishida Hospital, Oita, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kataoka
authors.forename: John E
authors.initials: JE
authors.lastname: Madias
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis; D001823:Body Composition; D001835:Body Weight; D016009:Chi-Square Distribution; D018450:Disease Progression; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000032:analysis; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain